J Agric Food Chem. 2008 Nov 12;56(21):10027-31D-chiro-inositol-enriched tartary buckwheat bran extract lowers the blood glucose level in KK-Ay mice.
Yao Y, Shan F, Bian J, Chen F, Wang M, Ren G.
Institute of Crop Science, Chinese Academy of Agricultural Sciences, No. 80 South Xueyuan Road, Haidian District, Beijing, People's Republic of China 100081.
D-chiro-inositol (DCI) is an active compound in tartary buckwheat [Fagopyrum tataricum (L.) Gaench] with an insulin-like bioactivity. The present study was performed to (i) prepare DCI-enriched tartary buckwheat bran extract (TBBE), (ii) evaluate its acute toxicity in mice, and (iii) examine its blood glucose lowering activity in diabetic mice. It was found that steaming buckwheat bran in an autoclave at 1.6 MPa and 120 degrees C for 60 min could significantly enrich the DCI level in TBBE from 0.03 to 0.22% and further to 22% after passage of the TBBE through activated carbon and ion exchange resins. An acute toxicity test demonstrated that the LD 50 of TBBE was >20 g/kg of body weight in mice, suggesting that TBBE was in general nontoxic and safe in mice. Male KK-A(y) mice (type 2 diabetic) and C57BL/6 mice (the control) were used to investigate the antidiabetic activity of TBBE. In KK-A(y) mice, the blood glucose, plasma C-peptide, glucagon, total cholesterol, triglyceride, and blood urea nitrogen (BUN) levels were significantly higher than those in the C57BL/6 mice. In addition, KK-A(y) mice showed an obvious decrease in insulin immunoreactivity in the pancreas. The present study clearly demonstrated that oral administration of DCI-enriched TBBE could lower plasma glucose, C-peptide, glucagon, triglyceride, and BUN, improve glucose tolerance, and enhance insulin immunoreactivity in KK-A(y) mice.

Biosci Biotechnol Biochem. 2008 Dec;72(12):3148-57Anti-inflammatory effect of buckwheat sprouts in lipopolysaccharide-activated human colon cancer cells and mice.
Ishii S, Katsumura T, Shiozuka C, Ooyauchi K, Kawasaki K, Takigawa S, Fukushima T, Tokuji Y, Kinoshita M, Ohnishi M, Kawahara M, Ohba K.
Department of Agricultural and Life Sciences, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan. ishiis@obihiro.ac.jp
In conducting an in vitro screening of ethanol extracts from various natural foods using a human colon cancer cell line (CoLoTC cells), an extract of buckwheat sprouts (ExtBS) was found to express significant anti-inflammatory activity. The anti-inflammatory activity of ExtBS was confirmed by oral administration of lipopolysaccharide (LPS) to mice. Inflammatory cytokines (interleukin 6 and tumor necrosis factor alpha) were markedly up-regulated in the spleen and liver from LPS-administrated mice, and combinatory treatment with LPS and ExtBS decreased up-regulation of them in both cytokines. Both serum cytokine levels corresponded to their gene expressions in tissues, but no anti-inflammatry effect in mice was observed when ExtBS was treated intraperitoneally. ExtBS oral administration also showed protective activity as to hepatic injury induced by galactosamine/LPS treatment. Based on these data, we suggest that ExtBS contains anti-inflammatory compounds.

Nippon Eiseigaku Zasshi. 2008 Jul;63(4):711-6Protective Effects of Buckwheat Hull Extract against Experimental Hippocampus Injury Induced by Trimethyltin in Rats
Koda T, Kuroda Y, Ueno Y, Kitadate K, Imai H.
Division of Environmental Health Sciences, Department of Social Medicine, Faculty of Medicine, University of Miyazaki.
Objectives: The main objective of this study is to clarify the protective effects of buckwheat hull extract (BWHE) against toxicant-induced spatial memory impairment and hippocampal neuron injury in rats. Methods: Male Sprague-Dawley (Jsl: SD) rats were fed chow containing 0.75% (w/w) BWHE during the experimental period. Two weeks after the start of the experiment, trimethyltin (TMT) (8 mg/kg bw) was administered orally to 6-week-old rats. After another two weeks, the rats were subjected to the Morris water maze task, which was used to determine spatial memory impairment. On the day after the Morris water maze task was performed, the right hemi-hippocampi were removed from the right half of the brain and weighed. Coronal sections of the left half of the brain were cut into 16-mum sections using a cryostat, and the number of neurons in each hippocampal region was evaluated by counting the surviving neurons using a light microscope. Results: The impairment of spatial memory and the decrease in the hippocampal weight were observed after the TMT administration. Prolonged supplementation of BWHE seemed to reverse these TMT-induced toxic effects, and also improved the spatial memory of rats. Conclusions: The present results suggest that the BWHE supplementation of foods enhanced the spatial memory of rats and may have protective effects against hippocampal neurodegeneration accompanied by spatial memory impairment.

J Nutr Sci Vitaminol (Tokyo). 2007 Dec;53(6):501-7Tartary buckwheat sprout powder lowers plasma cholesterol level in rats./b>
Kuwabara T, Han KH, Hashimoto N, Yamauchi H, Shimada K, Sekikawa M, Fukushima M.
The United Graduate School of Agriculture Sciences, Iwate University, Iwate, Japan.
We examined the effects of different types of buckwheat sprouts on the plasma cholesterol concentration, fecal steroid excretion and hepatic mRNA expression related to cholesterol metabolism in rats. Rats were fed a cholesterol-free diet with 5 g of Kitawasesoba common buckwheat sprout powder (KS)/100 g, 5 g of Hokkai T no. 8 tartary buckwheat sprout powder (HS-8)/100 g or 5 g of Hokkai T no. 9 tartary buckwheat sprout powder (HS-9)/100 g of diet for 4 wk. Control rats were fed a diet with alpha-cornstarch instead of sprout powder for 4 wk. There were no significant differences in food intake, body weight, liver weight or cecal contents among the groups. Plasma total cholesterol concentrations in the HS-8 and HS-9 groups were significantly lower than in the control group, whereas there was no significant difference between the KS and control groups. Fecal bile acid excretion and cecal short-chain fatty acid concentrations in the KS, HS-8 and HS-9 groups were significantly greater than in the control group. Furthermore, fecal matter excretion in the KS, HS-8 and HS-9 groups tended to be increased compared to the control group, with that in the HS-8 group being significantly higher than in the control group. Hepatic cholesterol 7alpha-hydroxylase mRNA expression in the KS, HS-8 and HS-9 groups and hepatic HMG-CoA reductase mRNA expression in the HS-9 group were significantly higher than in the control group. The results suggest that tartary buckwheat sprout powder has a serum cholesterol-lowering function by enhancing fecal bile acid excretion through increased fecal matter excretion or the upregulation of hepatic cholesterol 7alpha-hydroxylase mRNA expression in rats.

Phytomedicine. 2007 Aug;14(7-8):563-7Suppressive effects of germinated buckwheat on development of fatty liver in mice fed with high-fat diet
Choi I, Seog H, Park Y, Kim Y, Choi H.
Division of Food Resource Utilization, Korea Food Research Institute, San 46-1, Baekhyun-Dong, Bundang-Gu, Seongnam-Si, Kyunggi-Do 463-420, Korea. choiw@kfri.re.kr
Effects of buckwheat germinated for 48 h in suppressing fatty liver were investigated using an animal study. Concentration of rutin was increased more than 10 times, with production of quercitrin and one newly formed flavonoid during 48 h germination. When an ethanol extract of germinated buckwheat was fed daily to C57BL/6 mice at 100 or 200 mg/kg body wt, along with a high-fat diet, oral administration of germinated buckwheat caused significant reductions in TG and TC levels in the liver after 8 weeks. Oral administration of germinated buckwheat also down-regulated mRNA expressions of PPARgamma and C/EBPalpha in hepatocytes, in a dose-dependent manner. These results suggest that germinated buckwheat has potent anti-fatty liver activities caused partially by suppressing the gene expression of certain adipogenic transcription factors like PPARgamma and C/EBPalpha in hepatocytes.

Zhongguo Shi Yan Xue Ye Xue Za Zhi. 2007 Feb;15(1):59-62[Apoptosis of HL-60 cells induced by recombinant common Buckwheat trypsin inhibitor] [Article in Chinese]
Gao L, Li YY, Zhang Z, Wang ZH, Wang HW, Zhang L, Zhu L.
Key Laboratory for Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China.
The study was purposed to investigate the apoptosis of HL-60 cells induced by recombinant common buckwheat trypsin inhibitor (rBTI) and its mechanism. The inhibition rate of rBTI on HL-60 cells was detected by MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide); the morphology of HL-60 nuclei was observed by fluorescence microscopy; the apoptosis cells of HL-60 detected by agarose gel electrophoresis and the changes of apoptosis rate was assayed by flow cytometry (FCM), when the HL-60 cells were treated with different concentration of rBTI for 24 hours. The results showed that the growth of HL-60 cells was inhibited evidently after treatment with rBTI in a dose-dependent manner, but there were minimal effects on normal human peripheral blood mononuclear cells (PBMNCs). The nuclei of HL-60 cells showed the characteristics of apoptosis, the analysis by flow cytometry indicated that the apoptosis rate of HL-60 cells was 52% after treatment with rBTI (100 microg/ml), DNA analyzed by agarose gel electrophoresis showed "ladder" pattern. It is concluded that rBTI obviously inhibits growth of HL-60 and induces its apoptosis which provides a foundation for use of recombinant common buckwheat trypsin inhibitor to cure the acute myeloid leukemia.

J Agric Food Chem. 2003 Dec 3;51(25):7287-91Buckwheat concentrate reduces serum glucose in streptozotocin-diabetic rats.
Kawa JM, Taylor CG, Przybylski R.
Department of Human Nutritional Sciences, University of Manitoba, H505 Duff Roblin Building, 190 Dysart Road, Winnipeg, Manitoba, Canada R3T 2N2.
The antihyperglycemic effects of chemically synthesized d-chiro-inositol (d-CI), a component of an insulin mediator, have been demonstrated in rats. Buckwheat contains relatively high levels of d-CI: thus, it has been proposed as a source of d-CI for reducing serum glucose concentrations in diabetics. The present study evaluates the effects of a buckwheat concentrate, containing d-CI, on hyperglycemia and glucose tolerance in streptozotocin (STZ) rats. In fed STZ rats, both doses of the buckwheat concentrate (containing 10 and 20 mg of d-CI/kg of body weight) were effective for lowering serum glucose concentrations by 12-19% at 90 and 120 min after administration. Findings from this study demonstrate that a buckwheat concentrate is an effective source of d-CI for lowering serum glucose concentrations in rats and therefore may be useful in the treatment of diabetes.